The present invention relates to the printing of electrosensitive substrates, and more particularly to the advantageous design of electrosensitive label stock.
Electrosensitive papers are widely used as a printing substrate, with the advantages of high printing speeds at reasonable costs. Such substrates are typically composed of an electroconductive paper with a thin metallic overcoat. Printing occurs when a stylus bearing a desired image is brought into contact with the metallic surface layer, and a potential difference is applied between the stylus and a grounded member contacting a nearby portion of the conducting substrate. The resulting current flow is largely converted into heat at the vicinity of the stylus, resulting in a melting of the metallic layer and patterned exposure of the differently colored underlayer. This technique, however, has never heretofore been extended to the imprinting of label stock and similar, die-cut substrates.
Accordingly, it is a principal object of the invention to design label stock and other die-cut electrosensitive substrates which are amenable to imprinting by the method described above. Another object of the invention is that such label stock possess the requisite properties to permit proper removal of imprinted labels.